Gray EPS
Gray EPS is an insulating material made of EPS rigid foam with heat radiation absorber and a special product group of expanded polystyrene . In contrast to the widespread white EPS (commercially available "Styrofoam"), gray EPS contains additional infrared absorbers and reflectors (e.g. aluminum oxide , graphite or soot ). To achieve the insulating effect, it also uses the reduction in heat transport through thermal radiation to reduce heat conduction . The additive also improves the resistance to natural UV radiation , as it partially dissipates or absorbs the infrared radiation and thus heat and thus forms an additional insulator in addition to the air in the plastic cells.
The development of gray EPS is based on the knowledge that conventional styrofoam has reached its limits in terms of improving thermal conductivity . White EPS, which is filled with the cell gas air , achieves a thermal conductivity of 0.040 W / (m · K) at a bulk density of 14.5 kg / m³ according to the forecast curve of EN 13163. A thermal conductivity of 0.035 W / (m · K) can only be achieved with a bulk density of 27 kg / m³.
raw materials
As raw materials for the production of gray EPS, pearl-shaped polystyrene spheres are used, which already contain the thermal radiation absorber and the propellant gas pentane (iso- and / or normal pentane). The processing into panels or molded parts takes place in conventional production facilities for the production of EPS. Due to the lower thermal conductivity, the consumption of raw materials is reduced by about 1/3 compared to conventional EPS, thus conserving resources. In connection with the efficient thermal renovation of existing buildings, gray EPS enables extensive savings in heating and cooling energy.
Graphite and carbon black as additives to improve the thermal properties of PU and EPS foams were proposed as early as the end of the 1980s, but were not used until the end of the 1990s due to the higher price compared to unmodified EPS and further necessary improvements in fire behavior. Subsequently there were EPS raw materials with various heat radiation absorbers : BASF used graphite in its Neopor products, Ineos added carbon black to its Silver products and Sunpor added aluminum oxide to its Lambdapor products . In the meantime, graphite has established itself among all manufacturers.
properties
Gray EPS must meet the requirements of EN 13163 . It is in the building material class classified B 1 as flame-retardant according to the EN ISO 9239-1, free of CFCs , HCFCs , HFCs and formaldehyde and is therefore considered due to the balanced environmental energy balance as environmentally compatible as regards the production and processing.
Possible uses
Main application of the insulation boards made of gray EPS are mainly wall insulation (z. B. ETIC systems ) and interior insulation such as. Widespread in France and Belgium doublage (doubling) or cavity insulation bivalve masonry as in northern Germany, the United Kingdom and Ireland are common and referred to there as a cavity wall . In buildings that need to be insulated more and more, the material offers a structural advantage due to its thinner insulation material.
This building material is also used in the area of flat and pitched roofs , roof support systems (on- rafter insulation ) and attic insulation , especially in the construction of energy-efficient buildings, and makes a significant contribution to avoiding heating costs in passive or low-energy houses or as part of the energy- efficient renovation of existing buildings to minimize this significantly.
developments
Due to the need for better and better insulation of the thermal building envelope and the resulting increase in the thickness of the insulation material, an ever larger proportion of the built-in EPS insulation material with an increasing proportion of gray EPS was used at the beginning of the 2000s. In addition to Dow Chemical , BASF is also one of the innovation drivers for graphite-modified EPS. A decisive disadvantage when using the gray insulation panels in the facade area is the high level of surface heating. This makes a coating, such as the application of the reinforcement layer, impossible in direct sunlight, especially in summer, without costly shading during the coating work. To compensate for these disadvantages, many manufacturers have also coated the surface of the panels with reflective colors (silver, pink, white etc.) in order to significantly reduce heating.
Web links
Individual evidence
- ↑ Industrieverband Hartschaum: Environmental product declaration for EPS rigid foam (gray) with thermal radiation absorber
- ↑ EN 13163 Thermal insulation products for buildings - Factory made expanded polystyrene (EPS) products - Specification . Appendix F, Figure F.1.
- ↑ For example, U.S. Patent US4795763 (CELOTEX Corporation) of January 3, 1988 and International Patent WO1990006339 (Dow Chemical) of November 25, 1988
- ↑ For further improvements see, for example, the European patent EP863175B1 (BASF) from February 17, 1998
- ↑ KI - plastic information: Synthos: EPS gray with graphite instead of soot
- ↑ Energieinstitut Vorarlberg: Gray versus white polystyrene insulation panels